The U.S. Environmental Protection Agency (EPA) has recently passed a regulation requiring the proper disposal of used automotive oil filters. The used oil entrapped in the paper filters of these devices is deemed toxic. Approximately 88% of the residual oil can be extracted through draining and crushing. However, the EPA classifies any oil filter having more than 5% residual oil as being a hazardous waste. If the oil filter is to be buried in a landfill without extracting another 7-8% of the residual oil, stringent procedures must be followed. To squeeze another 7-8% of the residual oil from the filter would necessitate crushing it with a fifty-ton press. Neither of these solutions is economically viable.
A more practical solution, which would be in compliance with the law, would be to recycle these materials. At present, however, scrap metal dealers are unwilling or unable to accept the scrap metal contained in the filter, even though the steel is of high quality. Posing more of a difficulty, however, is the recovery of the oil and oil residues still contained within the steel jacket. Notwithstanding these problems, the staggering number of discarded automobile oil filters makes it imperative that a recycling solution be quickly found.
The creator of this invention believes that scrap metal dealers will in time be persuaded to accept the scrap steel from the filters. Remaining, then, is the problem of extracting at least 95% of the oil at a reasonable cost, i.e., without the expense of employing large crushing presses.
The present invention comprises a low-cost process and apparatus wherein the residual oil can be removed from automotive oil filters.
Oil which is residually trapped in the paper filter materials will not drain from the filter under pressure or by gravitational forces, due to the surface tension and the forces of attraction between the oil and paper molecules.
The current invention reflects the discovery that the entrapped oil in each filter can easily be drained therefrom by mounting the draining filters on a vibratory apparatus. The apparatus has means to impart a mechanically- or electrically-induced vibration to the oil filters. Vibration between the range of 100 Hz to 8,000 Hz or more has been found to break the weak surface tension forces between the oil and paper filter materials. The oil will then be able to drain from the oil filter due to gravitational force. This method is an extremely low-cost solution to the above-mentioned problem; all it requires is a simple, vertically disposed oil filter mounting board and a mechanical or electrical oscillator mounted thereon.
To further enhance the draining of the residual oil, the aforementioned system and method also feature an apparatus for circulating hot air or steam about the oil filters while they are vibrated. The heat imparted to the steel jacket of the oil filters is quickly transferred to the residual oil, causing the oil to become less viscous, and hence, freely flowing. In this manner, the resident oil is more easily drained from the automobile oil filters.